Yes, you can probe by mouse specific place of your rotor (i.e. corner or somethink) and you will get cooridnates of this point. Then use simple math to calculte the angle/angles. Another way is to calcuate the angle based on the flow time - assuming that at time t=0 you have angle alfa = 0, and now you have time t = t1 you can calculate current angle acording to the following formula: alfa_new = t1[s]*(omega[rpm]/60). If your rotor did a full revolution you need to substact 360 from alfa_new. Hope this help.